# US 10,308,585 B2 · Nitroxide hydroxylamine and phenylenediamine combinations as polymerization inhibitors for ethylenically unsaturated monomer processes

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- Number: US 10,308,585 B2
- Document ID: US10308585B2
- Status: Granted
- Kind: B2
- Application number: 16/143,956
- Filed: 2018-09-27
- Published: 2019-01-24
- Granted: 2019-06-04
- Earliest claimed: 2013-12-03
- Assignees: Ecolab USA Inc.
- Applicants: Ecolab USA, Inc.
- Inventors: David Youdong Tong
- Web page: https://patentgrep.com/patent/US10308585B2

## CPC

- C07C 67/62: Use of additives, e.g. for stabilisation
- C07C 7/20: Use of additives, e.g. for stabilisation
- C07C 45/86: Use of additives, e.g. for stabilisation
- C07C 51/50: Use of additives, e.g. for stabilisation
- C07C 231/22: Separation; Purification; Stabilisation; Use of additives (separation of optical isomers C07C231/20)
- C07C 253/32: Separation; Purification; Stabilisation; Use of additives
- C07D 211/94: Oxygen atom, e.g. piperidine N-oxide
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)

## Abstract

Polymerization inhibitor compositions are provided. The polymerization inhibitor compositions may include at least one hydroxylamine of a nitroxide and at least one phenylenediamine. Methods of inhibiting the unwanted polymerization of monomers are also provided. The methods include adding the presently disclosed polymerization inhibitor compositions to a fluid containing the monomers. The monomers may be ethylenically unsaturated monomers, such as acrylic acid, methacrylic acid, acrylonitrile, methacrylonitrile, acrolein, methacrolein, acrylate, methacrylate, acrylamide, methacrylamide, vinyl acetate, butadiene, ethylene, propylene, and styrene.

## Claims

### Claim 1

A method of inhibiting polymerization of butadiene comprising:
adding an effective amount of a polymerization inhibitor composition to a fluid comprising butadiene, wherein the polymerization inhibitor composition comprises an effective amount of 4-hydroxy-2,2,6,6-tetramethyl piperidinol and an effective amount of N,N′-di-1,4-dimethylpentyl-1,4-phenylenediamine; and
inhibiting polymerization of the butadiene.

### Claim 2 (depends on 1)

The method of claim 1, wherein the effective amount of the 4-hydroxy-2,2,6,6-tetramethyl piperidinol and the effective amount of the N,N′-di-1,4-dimethylpentyl-1,4-phenylenediamine is from about 1 ppm to about 2,000 ppm by weight of monomer.

### Claim 3 (depends on 1)

The method of claim 1, wherein the polymerization inhibitor composition is added continuously or intermittently to the fluid.

### Claim 4 (depends on 1)

The method of claim 1, wherein the polymerization inhibitor composition is added during an ethylene manufacturing process.

### Claim 5 (depends on 1)

The method of claim 1, wherein the polymerization inhibitor composition is added during a butadiene manufacturing process.